[Paul Coleman]

I know this sounds pretty basic but I would rather ask in case someone here has already done this.
It looks like I will shortly be moving my water production to a new location as the current one is no longer appropriate.  A carpeted wooden floor isn't ideal because no matter how much care is taken, an occasional accident with water seems inevitable.
However, it means that I will need to ditch my beloved IBC as it won't get through the doorway at the new place.  So I imagine I will need narrower tanks linked together.  I intend it to be unpumped and using a ballcock system as I currently do.  I had a bad experience once when a solenoid failed and the tank overflowed so my experience is not to rely on them.  There was a bit of dirt or scale in it and it did not cut out.
Anyway, that apart, I reckon I will need to link two (or possibly more) static tanks together as I would like 1,000 litre capacity.  I'm OK about losing a bit of this due to the gap caused at the top of the tank by the ballcock.
So I'm trying to work out the best way to do this.
Clearly the ballcock needs to go into the nearest tank to the mains inlet as it would be stopping the flow once it is sufficiently raised but I'm wondering at what height the link needs to be between tank 1 and tank 2.  It seems that I could either lose some of the capacity of tank 2 as I'm assuming that the water level would not rise above the height of the link.  Or, I could raise tank 1 higher and gravity feed tank 2.  However this would mean that if tank 2 was sealed with the lid on tightly, the water probably would not flow into it due to air pressure OR if air was allowed in to tank 2, tank 2 would overflow meaning that tank 1 would never fill and a flood from tank 2 would result.
Of course there is then the issue of the sub pump as it would need to be lifted from one tank to the other in order to fully load the van.  There are days when I get through a lot of water.
I'm probably being a bit dense.
I'm sure there are some pretty basic physics that I need to understand but I would rather ask if someone else has done this already and how best to do it.
Unless of course anyone is aware of a 1000ish litre water tank that will fit through a standard doorway.

[Ian Lancaster]

Not sure I follow, Paul, but if you just want to link two tanks together, then you need a pipe from the bottom of one to the bottom of the other.  It need to be at least 11/2" dia to allow the water to flow fast enough to balance the level in the two tanks.  The tanks need to be at the same level.

This in effect converts the two tanks into one tank.

As you draw water from one tank via your sub pump, water will flow from the other to balance the level.

Obviously the link has to be at the bottom, otherwise when the level in the second tank drops level with the link, no more water can flow through it.

I have two IBC's linked via the drain cocks at the bottom with a sub pump in one of them.  Works fine.

You could also have one tank on top of the other with the link from the bottom of the top tank going into the top (or bottom) of the bottom tank.  The sub pump would then be in the bottom tank

[richard jagger]

I would fit a overflow fitting and pipe to top of the 2nd tank to the outside of the building incase of over filling. I have this and it just runs out when to full.

[Paul Coleman]

Not sure I follow, Paul, but if you just want to link two tanks together, then you need a pipe from the bottom of one to the bottom of the other.  It need to be at least 11/2" dia to allow the water to flow fast enough to balance the level in the two tanks.  The tanks need to be at the same level.

This in effect converts the two tanks into one tank.

As you draw water from one tank via your sub pump, water will flow from the other to balance the level.

Obviously the link has to be at the bottom, otherwise when the level in the second tank drops level with the link, no more water can flow through it.

I have two IBC's linked via the drain cocks at the bottom with a sub pump in one of them.  Works fine.

You could also have one tank on top of the other with the link from the bottom of the top tank going into the top (or bottom) of the bottom tank.  The sub pump would then be in the bottom tank

I was trying to work this out because I was concerned that the fact that tank 2 would be sealed would mean that air pressure in tank 2 would prevent tank 2 from filling once the joining pipe was covered.  Mind you, having slept on it, even if this were the case, allowing a little air into (and out of) tank 2 by the top would be OK because the ballcock in tank 1 would prevent an overflow.  I believe that, as you say, the fatness of the link is key because that would prevent water getting "stuck" in tank 1 or flowing too slowly into tank 2.
I remember when I started out with WFP I had 2 x 250 litre tanks joined up as a van mount.  They were joined at the bottom though a very narrow pipe.  This was fine for working but not so good for filling.  This was because other equipment installed was obstructing the lid so it took ages to equalise.  I had to pause from filling for ages.
Seems I was having a rather tired, brainless time last night when I posted  as I should have recalled this before posting    .

[Andy@w.c.s]

http://www.quickreach.co.uk/acatalog/1050natural-rgl.jpg

Have a look at the above link hope this might help


Andy